StSnRK1.1 protein kinase positively regulates tuber dormancy release of potato

SnRK1 is a plant-specific serine/threonine protein kinase, that plays a vital role in maintaining the energy balance, nutrient distribution, growth, and development of organisms for survival. The period of tuber dormancy seriously affects potato production. To elucidate the effect of the StSnRK1.1 gene on dormancy release, the gene was cloned from the potato cultivar 'Desiree', and the overexpression and interfering expression lines were obtained through genetic transformation. StSnRK1.1 promoted early dormancy release and sprouting of potato tubers in the overexpression line, while it delayed tuber sprouting in the StSnRK1.1-interfering expression line. In addition, it was discovered that abscisic acid (ABA) in the StSnRK1.1 overexpression line was significantly reduced compared with the wild type plants, while the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased. Conversely, the opposite result was found in the StSnRK1.1 gene interference expression line, which indicated that the dormancy release was accelerated, the reactive oxygen species metabolism efficiency was high, and the reactive oxygen species could be quickly removed and the accumulation of reactive oxygen species could be avoided during the dormancy release process. The positive regulatory genes StSnRK2.2 and StABI5 of ABA signal transduction were lower than those of wild type in the overexpression line and higher than that of the wild type in the interfering expression line, while the negative regulatory genes StPP2CA1 and StPP2CA3 of ABA signal transduction were higher than those of the wild type in the overexpression line and lower than that of the wild type in the interfering expression line. In summary, StSnRK1.1 affects ABA signaling by mediating the expression of StSnRK2.2, StABI5, StPP2CA1 and StPP2CA3, which provides a theoretical basis for the molecular mechanism of StSnRK1.1 to positively regulate the release of potato tuber dormancy. Through yeast two-hybrid (YH2) screening, two interacting proteins, StCAT3 and StFBA1, were identified. The interaction between StCAT3, StFBA1 and StSnRK1.1 was confirmed through bimolecular fluorescence complementation. These results provide novel information for further study on the molecular mechanism of StSnRK1.1 regulating dormancy and germination of potato tubers.